OFDM Receiver example In Gnuradio

Hallo,
I have a question related to the ofdm receiver example in gnuradio.
I put a delay block before Schmidl_Cox synchronizer and I changed it. After 7 samples delay the system beginns to produce errors and for the delay of 9 samples the system is dropped.
Did we miss the trigger signal because of the delay or there is another reason.
I am doing this in the baseband and without the RF transmission.
I want to check the system if there are a degradation effects, like delay ,frequency offset.
I have uploaded a foto of it.
Thanks !
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